A track ball device is a tool for controlling a movement of the cursor, which includes therein a global object called track ball. A general track ball has a diameter of about 1.5-2.0 cm, and is used in a personal computer for functioning like a traditional mouse device.
As for the video games, the track ball generally has a larger diameter of about 10 cm. There are two types of video game track balls, one is a hollow structure and the other is a solid structure. The hollow track ball includes two hemispherical shells which have the advantage of light weight but present therebetween an untidy joint portion due to the combination thereof. Accordingly, the solid track ball is introduced to avoid the appearance of a joint seam. But, such a prior solid track ball has a drawback that the entire solid body is made of Acrylonitrile-Butadiene-Styrene (ABS), which is relatively heavy, not effective in material, and uneasy in operation.